The spread of the Eurasian lineage of H5N1 highly pathogenic
avian influenza (HPAI) from China to other countries
across Asia, Europe, the Middle East, and Africa is an unprecedented
epizootic event. Although the initial outbreaks
of H5N1 HPAI virus in Hong Kong, China, were successfully
eradicated in late 1997 [1], the virus re-emerged in